Plastic blow molded containers for holding carbonated beverages when first used commercially were manufactured as base cup containers wherein the lower extremity of the blow molded container has a hemispherical shape that is received within an injection molded plastic base cup that supports the container during use. Such a base cup permits the hemispherical shape to be utilized to provide the requisite strength for withstanding the internal pressure from carbonated beverages while still providing a flat surface on which the container can be supported in an upright position. While such containers functioned satisfactorily, there is a cost involved in both manufacturing and assembling the base cup to the blow molded container and such cost must necessarily be included in the price to the consumer.
Blow molded containers capable of withstanding pressure have also been manufactured with freestanding base structures that are unitary with the container body and having legs with lower flat feet separated by curved ribs as disclosed by U.S. Pat. Nos.: 5,064,080 Young et al.; 5,139,162 Young et al.; 5,287,978 Young et al.; and 5,615,790 Young et al. These Young et al. patents disclose a hollow leg, curved rib, and central hub construction that has particular utility in withstanding internal pressure generated by carbonated beverage while also having good stability that resists tipping even when empty prior to filling. During such filling, increased speeds for providing greater filling capacity has a tendency to cause tipping which is disadvantageous. The construction disclosed by the Young et al. patents in part prevents tippage by having the lower flat feet provided with an outer extremity that has a relatively large diameter with respect to the diameter of the container body portion that extends upwardly from the freestanding base structure to an upper end closure in a unitary manner.